The present invention relates to a propping device of a turboset, particularly a high-temperature helium turbine comprising of a compressor and a generator coupled thereto, the turboset being arranged in a prestressed pressure vessel, preferably a prestressed concrete pressure vessel, and the pressure vessel being supported on a foundation.
In power station systems now in use, more particularly in systems using high-temperature helium turbomachines, the reactor core, the heat exchangers and, therebelow, one or more turbines, are housed in horizontal galleries. The turbines may be installed in various ways, e.g. in star formation, axially parallel to one another, or one behind the other. In all of these arrangements the components of the main circuit are housed in a prestressed concrete containment.
In these prior art systems, the turbomachines, mounted on special trolleys for assembling and dismantling, are pushed into the prestressed-concrete gallery. These trolleys run on rails mounted on the liner of the lower part of the gallery. By way of example, the turbomachine is so arranged that the gas inlet to the compressor is close to the reactor outlet. When the turbine has been installed, the gallery is sealed off by a pressure-resistant concrete plug. The turbine housing, consisting of an upper and a lower half, is supported coaxially within the gallery in multiple planes.
This results in a number of drawbacks which are caused in part by the fact that, due to the prestressing on the circumference and to the bracing cables arranged in the vertical direction, the prestressed concrete pressure vessel is deformed elastically and plastically, with the result that in the majority of cases the axis of the gallery is subject to sagging. The turbomachine itself can only be aligned after the prestressing of the concrete vessel has taken place. The deformations of the prestressed concrete vessel occurring throughout the operation and caused by operating influences, such as pressure and temperature of the working circuit, are difficult to evaluate beforehand. However, these deformations return to the original state when the machine has been shut down, that is to say, after removal of the pressure and temperature effects. However, after a fairly long operation period, there appears an extra permanent deformation caused by the relaxation of the prestressed concrete vessel, the extent of which cannot be accurately predicted.
Another drawback is that the gallery cannot be placed in the neutral zone of the substantially vertically mounted prestressed concrete vessel which houses the reactor. In this case, one would not have to fear a deformation of the horizontal axis of the gallery. However, since this space is occupied by the integrated reactor core, such an arrangement cannot be realized. By disposing the gallery below the reactor cavern in the lower half of the prestressed concrete vessel, i.e., in a horizontal direction and perpendicular to the longitudinal axis of the vessel, a peripheral position of the gallery is obtained in the lower half of the prestressed concrete vessel, so that a deflection of the gallery axis must be reckoned with. Now, when the turbomachine is supported directly in the gallery, it sags together with the gallery in service. In addition, the longitudinal axis of the generator can be displaced in relation to the position of the turbomachine shaft owing to the deformation of the prestressed concrete vessel. These motions cause a deformation both in the turbomachine casing and in the whole power assembly shaft, resulting in an extra load onto the shaft bearing.